900 APPENDIX. 
their action in the fermentation of sugar, Three of the plants 
curiously enough belong to the natural order Oleacex ; these are Olea 
glandulifera, jasminum and ligustrum, and like other plants of this 
order contain a peculiar bitter principle, soluble in water and alcohol, 
and a yellow colouring matter called quercetin. Two other barks of 
the series belong to the same natural family of the laurels, and have a 
similar composition ; these are the Litseas. The Hiptage bark con- 
tains tannin, and is simply an astringent; and the Gmelina belongs 
to a class of plants distinguished for their bitterness, 
“the amount of extract dissolved out of the bark by water and 
alcohol respectively were determined in order to ascertain their 
relative proportion, as it would seem that in the absence of much 
resin, the excess of water extract over the spirit extract would 
indicate mucilaginous matter, and on the barks being placed in the 
toddy, which in a fresh state is a watery solution of sugar, with some 
albuminous matter, the extract would dissolve, but as fermentation 
proceeded, alcohol would be formed and the mucilage would become 
insoluble and precipitate, carrying down with it the viscid albumen, 
and thus allow the sugar to ferment more rapidly, From the fact 
that other gum-barks besides the Litswas, such as Kydia calyeina 
and Guazuma tomentosa, are largely used in clarifying sugar, it is 
evident that some such object as this is intended in their employment. 
The astringent qualities of most of the above-mentioned barks are no 
doubt used for the purpose of forming insoluble compounds with 
buminous matter in saccharine solutions; just as hops are used to 
remove this substance from malt liquor in the ordinary process of 
brewing beer. The hops are found to prevent in a great measure 
the tendency of the beer to become sour, in consequence of the 
conversion of alcohol into acetic acid, and in warm climates where 
such liquors are apt to run into the acetous fermentation very 
rapidly, it is necessary to employ astringent drugs to regulate the 
formation of alcohol and prevent the development of acetic acid, 
The natives consider these barks a necessary ingredient in making 
spirit, for the following reasons: Firstly, they diminish the great 
sweetness of the toddy sugar. Secondly, they render the spirit more 
intoxicating. The first of these phenomena is accounted for by the 
chemical fact that sugar breaks up during fermentation into two 
other bodies, aleohol and carbonic acid; and in the second place the 
barks enable the operator to obtain a larger 5 tion of alcohol from 
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